The short answer: put one line item per spreadsheet row, give rows from the same invoice the same invoice number, then upload the file to a bulk invoice generator like Fast Invoice Maker's bulk page. You get every invoice back as PDFs in a single zip, up to 100 invoices per batch, free with a watermark.
Bulk generation is the feature almost no invoice tool offers on a free tier, yet it is exactly what you need at the end of the month: tutoring businesses billing every student, agencies billing retainers, landlords billing tenants, clubs billing members. Making those one by one in accounting software is an afternoon of copy-paste.
How to lay out the spreadsheet
Use one row per line item with these columns. Only four are required:
| Column | Required | Notes |
|---|---|---|
| Invoice Number | Yes | Rows sharing a number become one invoice |
| Invoice Date | No | Best as YYYY-MM-DD; blank means today |
| Customer Name | Yes | Who the invoice bills |
| Customer Address | No | Shown under the name |
| Currency | No | 3-letter code like USD or MYR |
| Description | Yes | The line item text |
| Amount | Yes | Line amount before tax |
| Tax % | No | One rate per invoice, read from its first row |
How line items group into invoices
This is the part people ask about most. Each row is one line item, not one invoice. Consecutive rows that share an invoice number are combined into a single invoice with multiple lines. You can leave the invoice number, date and customer blank on the second and later rows of the same invoice; they carry over from the first row.
So an invoice with three line items takes three rows, and 40 single-line invoices take 40 rows. A new invoice starts whenever a row has a different invoice number.
Step by step
- Download a sample. The bulk page has XLSX and CSV samples with the exact columns, including a two-line invoice you can copy.
- Fill in your rows. Export from your booking system, CRM or just type them. Column names are matched loosely: "Inv No", "Client" and "Price" all work.
- Enter your company details once. Name, address, logo, default currency and terms apply to every invoice in the batch.
- Upload and review. You get a preview table showing every detected invoice with its total, plus row-numbered errors for anything that needs fixing.
- Download the zip. Each invoice is a separate PDF named after its invoice number.
The mistakes that break bulk imports
- Dates in ambiguous formats. 03/04/2026 means different things in different countries. Use YYYY-MM-DD (2026-04-03) and there is no ambiguity.
- Currency symbols inside amounts. "$1,200.00" imports fine in Fast Invoice Maker (symbols and commas are stripped), but plain numbers are safest across tools.
- Reused invoice numbers across different customers. Rows with the same number merge into one invoice, so accidental duplicates combine two customers' charges. Keep numbers unique per invoice.
- Blank rows between invoices. Fully blank rows are ignored, but a row with only an amount and no description will be flagged as an error.
What it costs
Free batches include the watermark on every PDF. To get clean files you can subscribe from USD 4 per week, or pay USD 0.99 once, which covers an entire batch, not just one invoice. For a monthly billing run of 60 invoices, that is under two cents per invoice. See pricing.